1. Field of the Invention
The present invention relates to an apparatus having a plurality of component parts interchangeably disposed in a plurality of component positions, respectively, and a method of controlling interchange between component parts in the apparatus.
2. Description of the Related Art
Conventionally, an image forming apparatus needs replacement of a component part in use when the service life of the component part expires. In such a case, when the image forming apparatus notifies the user of the need to replace the component part, the user informs a service person of the fact, and the service person replaces the component part. Alternatively, the service person detects a component part with only a short remaining service life by referring to counter information during regular maintenance, and replaces the component part without being notified by the image forming apparatus of the need to replace the component part. Particularly, feed rollers, conveying rollers, and retard rollers are more likely to wear than the other component parts, and hence they tend to inevitably need replacement more frequently.
Recently, in place of a business form in which a service person is indispensable for parts replacement, installation, or regular maintenance, a serviceless business form employed in compact segment devices has been coming into use for apparatuses with a large print volume. With this tendency, it is expected that regular consumable parts will be made into kits or units so as to facilitate replacement work by users, whereby replacement of the regular consumable parts, which has been conventionally performed by a service person, will be more and more often performed by each user himself/herself.
If the parts replacement by the user is realized, it can be envisaged that even when an image forming apparatus notifies the user that there is a component part whose service life has expired and recommends the user to replace the component part, the user will not replace the component part with a new one insofar as he/she can normally use the image forming apparatus.
As a consequence, the continuous use of the component part whose service life has expired can cause new abnormality (e.g. frequent occurrence of print jams) that cannot be recovered only by the parts replacement, and eventually work by the service person can be additionally necessitated.
Further, component parts are different in use frequency and hence are also different in the length of remaining service life. Therefore, if a notification is issued whenever a component part whose service life has expired is detected, work load applied to the user will probably be increased.
To eliminate the above-mentioned inconveniences, when an image forming apparatus is provided with a plurality of sheet feeding mechanisms which have the same function and enable the user to select any of them in perform an image forming operation in a desired out form, there has been proposed a technique of preferentially using a sheet feeder which is least frequently used (see Japanese Patent Laid-Open Publication No. 2001-005351). According to this technique, the wear degrees of component parts of the mechanism are made uniform. More specifically, when a component part having a short remaining service lifer is detected, the subsequent usage rate of the component part is caused to be reduced.
Further, Japanese Patent Laid-Open Publication No. H11-327381 discloses a printing system which uses a technique for storing a history and the like of regular replacement parts and component parts replaced due to failure, in an image forming apparatus thereof. This printing system is comprised of a means for identifying the individual identities of respective replacement component parts, a means for counting the remaining service life of each component part and storing the count, a means for counting an accumulated replacement count, and a means for storing the history of the count indicative of the remaining service life after replacement and the accumulated replacement count of each component part.
However, the above-described conventional image forming apparatus suffers from the following problems: When the technique disclosed in Japanese Patent Laid-Open Publication No. 2001-005351 is employed, e.g. in a case where A4-size sheets are designated for all the four sheet feeders of an image forming apparatus having a 4-stage sheet feeding mechanism, it is possible to automatically select a sheet feeder to be preferentially used. However, when sheet sizes designated for the respective sheet feeders are different from each other, it is expected that there cannot be found any sheet feeders which can be automatically selected.
Further, in a case where the technique disclosed in Japanese Patent Laid-Open Publication No. 2001-005351 is employed for a user who intends to reduce a first print time by feeding A4 sheets from the uppermost sheet feeder, automatic selection can make the first print time longer than before the automatic selection e.g. when the lowermost sheet feeder is automatically selected to feed A4-size sheets therefrom.
When the technique disclosed in Japanese Patent Laid-Open Publication No. H11-327381 is employed, it is possible to store a count indicative of a remaining service life and a replacement history in association with an identification means uniquely assigned to each component part. However, when a component part in use is not replaced with a new article, but interchanged with another component part in use e.g. based on operational conditions, the identification means cannot be taken over, which makes it impossible to keep matching with respective histories of the parts before the interchange.